I don't know the song, but using the lyrics you gave I tracked this down with Google - could this be the missing bit?"..at times we're rather mean and at times..."
From http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=WCHG19390401.2.4.19&cl=CL1.WCHG&e=20-09-1910-01-12-1910--10--11-byDA---0Government+House+drains--